Workers at the JBS Souderton Beef Processing and Rendering Plant on Allentown Road in Franconia have joined a union. The United Food and Commercial Workers Local 1776, based in Plymouth Meeting, represents about 1,200 workers at the plant, known as Smithfield’s Mopac Unit until the Brazilian company JBS bought Smithfield two years ago. Long-time employee Bernard Coneghen issued a statement saying they spoke with union representatives about the benefits of having a voice at work and voted to join.